<script>
import getPowerSet from "@/vernder/power-set";
export default {
    name: 'GoodsSku',
    emits: ['change'],
    props: {
        goods: {
            type: Object,
            default: () => ({ specs: [], skus: [] })
        },
        skuId: {
            type: String,
            default: ''
        }
    },
    setup(props, { emit }) {
        const clickSpecs = (item, val) => {
            if (val.disabled) return false
            if (val.selected) {
                val.selected = false
            } else {
                item.values.forEach(bv => { bv.selected = false })
                val.selected = true
            }
            updateDisabledStatus(props.goods.specs, pathMap)
            // 触发change事件将sku数据传递出去
            const selectedArr = getSelectedArr(props.goods.specs).filter(v => v)
            if (selectedArr.length === props.goods.specs.length) {
                const skuIds = pathMap[selectedArr.join(spliter)]
                const sku = props.goods.skus.find(sku => sku.id === skuIds[0])
                // 传递
                emit('change', {
                    skuId: sku.id,
                    price: sku.price,
                    oldPrice: sku.oldPrice,
                    inventory: sku.inventory,
                    specsText: sku.specs.reduce((p, n) => `${p} ${n.name}：${n.valueName}`, '').replace(' ', '')
                })
            } else {
                emit('change', {})
            }
        }
        const spliter = '★'
        // 根据skus数据得到路径字典对象
        const getPathMap = (skus) => {
            const pathMap = {}
            skus.forEach(sku => {
                // 1. 过滤出有库存有效的sku
                if (sku.inventory) {
                    // 2. 得到sku属性值数组
                    const specs = sku.specs.map(spec => spec.valueName)
                    // 3. 得到sku属性值数组的子集
                    const powerSet = getPowerSet(specs)
                    // 4. 设置给路径字典对象
                    powerSet.forEach(set => {
                        const key = set.join(spliter)
                        if (pathMap[key]) {
                            // 已经有key往数组追加
                            pathMap[key].push(sku.id)
                        } else {
                            // 没有key设置一个数组
                            pathMap[key] = [sku.id]
                        }
                    })
                }
            })
            return pathMap
        }
        // 得到当前选中规格集合
        const getSelectedArr = (specs) => {
            const selectedArr = []
            specs.forEach(spec => {
                const selectedVal = spec.values.find(val => val.selected)
                selectedArr.push(selectedVal ? selectedVal.name : undefined)
            })
            return selectedArr
        }
        // 更新按钮的禁用状态
        const updateDisabledStatus = (specs, pathMap) => {
            specs.forEach((spec, i) => {
                const selectedArr = getSelectedArr(specs)
                spec.values.forEach(val => {
                    // 已经选中的按钮不用判断
                    if (val.name === selectedArr[i]) return false
                    // 未选中的替换对应的值
                    selectedArr[i] = val.name
                    // 过滤无效值得到key
                    const key = selectedArr.filter(v => v).join(spliter)
                    // 设置禁用状态
                    val.disabled = !pathMap[key]
                })
            })
        }

        // 初始化选中状态
        const initSelectedStatus = (goods, skuId) => {
            const sku = goods.skus.find(sku => sku.id === skuId)
            if (sku) {
                goods.specs.forEach((spec, i) => {
                    const value = sku.specs[i].valueName
                    spec.values.forEach(val => {
                        val.selected = val.name === value
                    })
                })
            }
        }
        const pathMap = getPathMap(props.goods.skus)
        initSelectedStatus(props.goods, props.skuId)
        updateDisabledStatus(props.goods.specs, pathMap)
        return { clickSpecs }
    }
}
</script>

<template>
    <div class="goods-sku">
        <dl v-for="item in goods.specs" :key="item.id">
            <dt>{{ item.name }}</dt>
            <dd>
                <template v-for="val in item.values" :key="val.name">
                    <img :class="{ selected: val.selected }" @click="clickSpecs(item, val)" v-if="val.picture"
                        :src="val.picture" :title="val.name">
                    <span :class="{ selected: val.selected }" v-else @click="clickSpecs(item, val)">{{ val.name }}</span>
                </template>
            </dd>
        </dl>
    </div>
</template>

<style scoped lang="less">
@import '@/assets/styles/variables.less';

.sku-state-mixin () {
    border: 1px solid #e4e4e4;
    margin-right: 10px;
    cursor: pointer;

    &.selected {
        border-color: @xtxColor;
    }

    &.disabled {
        opacity: 0.6;
        border-style: dashed;
        cursor: not-allowed;
    }
}

.goods-sku {
    padding-left: 10px;
    padding-top: 20px;

    dl {
        display: flex;
        padding-bottom: 20px;
        align-items: center;

        dt {
            width: 50px;
            color: #999;
        }

        dd {
            flex: 1;
            color: #666;

            >img {
                width: 50px;
                height: 50px;
                .sku-state-mixin ();
            }

            >span {
                display: inline-block;
                height: 30px;
                line-height: 28px;
                padding: 0 20px;
                .sku-state-mixin ();
            }
        }
    }
}
</style>